Cycle Time Reduction: Drilling with C-Axis Unclamped (Lathes)
03.29.2017
In my previous blogs I’ve talked about ways to increase production on Okuma CNC lathes using cycle time reduction when commanding the spindle/M-spindle, and when indexing a lathe turret. Now I’d like to show you two ways you can improve cycle time when drilling multiple holes with a compound fixed cycle (G181).
When drilling and cutting forces are small, such as small diameters or in aluminum, cycle time can be reduced by drilling with the C-axis unclamped.
Both methods below allow compound fixed cycle drilling without clamping the C-axis, but one is ideal for high-volume low-mix production, while the other works better for low-volume high-mix. You can always reference your “OSP-P300L/P300S Operator’s Pocketbook” for this information, but I’m spotlighting it here to give you some quick, actionable tips.
Method 1: Change the Parameter Setting (Modal)
This method is ideal for high-volume, low-mix scenarios, where processes have already been proven to work without C-axis clamping.
Set the OPTIONAL PARAMETER: (MULTIPLE MACHINING) "C-axis clamp/unclamp in hole pro." parameter to "no effect".
Method 2: Use M-Code M141 (by block)
This method is ideal for low-volume, high-mix scenarios, where clamping the C-axis can only be omitted in some cases.
Use the M141 command in the program to disable the C-axis clamp/unclamp command in the block where the M141 command exists.
Warning
- If you are drilling larger holes or in a situation where higher forces are exerted, the C-axis may be displaced by the cutting forces.
- Since C-axis clamping and unclamping is not performed, the tool could interfere with the work piece if the retraction distance is not adequate and/or droop is not enabled. Set an appropriate retraction distance for the Z-axis and/or set the droop control of the feed axis to "enabled" and set a permissible value.
Where Half a Second Can Really Make a Difference
The shops that will benefit most from these techniques are those where seconds off a cycle equals tens of thousands of dollars saved over a year, but anyone armed with this knowledge can take advantage of these little time-savers.
Thoughts? Questions? Feel free to let me know in the comments below.
Cooper Ferguson is Applications Engineer, Okuma America Corporation.
Read the other blogs in Cooper’s series on Cycle Time Reduction:
Tips for Cycle Time Reduction: Spindle/M-Spindle
Cycle Time Reduction: Indexing Turret